With that one stroke, the SEC would fill the regulatory void the U.S. Supreme Court created in 2010 when it freed corporations to spend unlimited money to influence elections, but ruled it would be permissible to require disclosure. Candidates are required to report contributions from individuals and political action committees, including those associated with corporations. But companies do not have to disclose their independent political spending. People deserve to know who's bankrolling all efforts to sway their votes.

White, whom the Senate confirmed Monday by unanimous consent, should see to it that the SEC writes a disclosure rule and then use her influence on the five-member commission to get it approved.

Corporations and independent groups spent an estimated $400 million to sway campaigns in 2012. Requiring disclosure by publicly held companies the SEC regulates wouldn't turn a spotlight on all that money in future elections, since some will be spent by other types of groups. Only Congress can do that. Its members should put the public's interest in disclosure before the anonymity of big-money supporters. If they don't, SEC regulation may be the most sunlight the public can get.

New York Attorney General Eric T. Schneiderman is moving to require nonprofit "social welfare" organizations that do business in the state to disclose how much of their spending goes to electioneering and, in some circumstances to identify their contributors. But unlike Schneiderman, the SEC's reach is national.

In the political arena, the U.S. Supreme Court ruled money is protected First Amendment speech. To know who's talking, voters have to know who's spending.